Tube connection for rock drills



TUBE commcnon FOR ROCK bnILLs Fild Nov. 18. 1926 I INVENTVOR. I

, 1,637,204 F. M. SLATER Imam Slate 12% HIS ATTZNLY' Patented July 26,1927.

UNITED STATES PATENTOFFICE.

FRED M. SLATER, OF EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLL-RAND COM-PANY, OF JERSEY CITY, NEW JERSEY, A

CORPORATION OF NEW JERSEY.

TUBE CONNECTION FOR ROCK DRILLS.

Application filed November This invention relates to rock drills, butmore particularly to a tube connection for fluid actuated rock drills ofthe hammer type in which a pair concentrically arranged fluid conveyingtubes are disposed through the percussive element to communicate withtheir front ends with a hollow drill steel for delivering cleansingliquid thereto.

The objects of the invention are to securely hold a pair ofconcentrically arranged tubes in the back head of a rock drill in asimplified and improved manner, to simplify the construction and reducethe cost of manufacturing connections of this type, and to render theparts which comprise the con nection incapable of being improperlyassembled.

Other objects will be in part obvious and in part pointed outhereinafter.

The invention consists of the'combinations of elements, and arrangementof parts sul stantially as hereinafter described and claimed andillustrated in the accompanying drawings in which Figure 1 is anelevation, partly in section,

of a rock drill equipped with a connection constructed in accordancewith the practice of the invention, and

Figure 2 is an enlarged detail sectional elevation of the back head andthe tube connection. 1

Referring to the drawings, the invention is shown embodied in a rockdrill having a cylinder A which supports at its rearward end a back headB and at its forward end a front cylinder extension C. The front end ofthe cylinder extension C supports a front head D in which is disposed achuck F. The rearward portion G of the chuck F is in this instance ofsmaller diameter than the forward portion and extends into the cylinderextension C to provide a seat for an anvil block H interposed between ahammer piston J and a hollow drill steel K for trans mitting the blowsof the piston to the drill steel.

Any suitable means may be provided for securing the casing parts of thedrill, such as the cylinder A, the back head B, the front cylinderextension C and the front head 1), together. In the drawings, bolts L,only a ortion of one of which is shown, are provided for this purposeand these bolts may be held in assembled position by suitable 18, 1926.SeriaI No. 149,127.

2' P jections 0 formed on the casing cylindrical portion It. Leadingfrom the bottom of the recess P through the back head B is a hole Sthrough which extends slidably an air tube T. At the rearward end of theair tube T is formed a flared por ion U which cooperates with a taperedseat V at the juncture of the hole S and the recess P to form a fluidtight joint for preventing leakage of cleansing liquid, such as water,from the recess into the cylinder A. tube T is preferably of a length toextend with its front end to a point slightly rearwardly of the drillsteel when said dril'l steel is in its rearwardmost limiting position.

Disposed concentrically within the tuge T is a water tube \V of somewhatsmaller diameter than the bore of the tube T having slightly reduced endX which extends into the hollow bore of the drill steel K. The tube Wcarries a flange Y near its rearward end, thus leaving an end Zprojecting rearwardly of the flange which extends slidably into a bore 6of a water plug 0 for holding the said tube concentrically within thetube T.

The water plug 0 also serves to seal the recess P and istapered at itsforward end (1 to form a chamber 6 in the recess P for the reception ofwater which may be conveyed into the drill through a conduit f leadingfrom a suitable source of supply (not shown). A passage 9 in the backhead B affords communication between the charm ber c and the conduit f.

A passage 71, leading from the tapered portion of the plug a to therearward end of the bore Z) into which the tube V extends serves toconvey the water from the chamber a to the water tube W.

In connections of this type, considerable difliculty is at timesexperienced, due to leakage of water from the back head into thepercussive cylinder. The results of such leakage on the movable parts ofthe rock drill are well known. Various means have heretofore beendevised for forming a perfect seal between the water tube connection andthe cylinder. Such means, however, are usually of rather complicatedconstruction The and requirea multiplicity of parts which in crease thecost of construction considei'alily. The present invention ainis toovercome these limitations and to this end a plug jis disposed intliefront or inner end of the recess P aiid has a tapered portion iiiwhichfits into the flared end of the tube T. The plug j is provided with acentral aperture 0 through which the Water tube W ex: tends and thisaperture 0 is preferably of such diameter throughout its length that theplug j will not contact with the tube W. In the present instance, theplug 7' is provided with a transverse passage p which atfordscommunication between the aperture 0, and the front or inner end of therecess P for conveying pressure fluid to the tube T, such pressure fluidbeing conveyed to the recess P through a passage Q adapted tocoinniuiiicate with any suitable source of pressure fluid supply. Arubber packing r is disposed between the flange Y of the tube \V and theplug j for preventing leakage of Water from the chamber e into the innerend of the chamber By means ofthe present invention, leakage of waterfrom the hack head into the cylinder will be entirely prevented. This isdue largely to the novel inanner which the tubes niay be secured in,position and also to the simple machining operations which thisconstruction permits, Additiom aladvantages of the present invention arethat in the event that excessive force be applied the ater plu" 0 forscrewing it into the recess P, there \villbeno likelihood, of breakageof' any parts to which such force'is transmitted, the parts comprisingthe connection are constructedwitha View of preventing improperassemblyof the connection, and there are only a few parts required to obtain allthe desirable features sought for in devices of this character,

I claini: i

In a fluid actuated rock drill, thecombination of a cylinder, a backhead for the cylinder having a recess, a tapered seat-in the bottoni ofthe recess, a pair of concentrically arranged tubes extending throughthe cylinder and'into the recess, a flared portion on the outer tube tocooperate with the taliered seat for forming a fluid tight joint; aflange on the inner tube, a tapered plug seated in the flared end of theouter tube and loosely encircling the inner tube, a packing between thetapered plug and'the' flange, anda water ping screwed in the recessbearing on the flange to compress the acking and to hold the taperedbore and the flared portion of the outer tube firmly on their seats,said water plug having an aperture toreceive the rearward end of theinner tube for holding said inner tube concentrically with respect totheouter tube.

In testimony whereof I have signed this specification.

FRED M; SLATER.

